Spatial and temporal regulation of protein kinase D (PKD)

Abstract

Protein kinase D (PKD; also known as PKCmicro) is a serine/threonine kinase activated by diacylglycerol signalling pathways in a variety of cells. PKD has been described previously as Golgi-localized, but herein we show that it is present within the cytosol of quiescent B cells and mast cells and moves rapidly to the plasma membrane after antigen receptor triggering. The membrane redistribution of PKD requires the diacylglycerol-binding domain of the enzyme, but is independent of its catalytic activity and does not require the integrity of the pleckstrin homology domain. Antigen receptor signalling initiates in glycosphingolipid-enriched microdomains, but membrane-associated PKD does not co-localize with these specialized structures. Membrane targeting of PKD is transient, the enzyme returns to the cytosol within 10 min of antigen receptor engagement. Strikingly, the membrane-recycled PKD remains active in the cytosol for several hours. The present work thus characterizes a sustained antigen receptor-induced signal transduction pathway and establishes PKD as a serine kinase that temporally and spatially disseminates antigen receptor signals away from the plasma membrane into the cytosol.

Stimulation of the neurokinin 3 receptor activates protein kinase Cε and protein kinase D in enteric neurons

“…2, A and AЈ). This is consistent with previous reports that used isolated cells (25,26). PDBu induced prominent membrane-associated phospho-PKD 916 labeling.…”

“…PKD, together with PKCε, can phosphorylate the transient receptor potential/vanilloid channel of nociceptive neurons, resulting in hyperalgesia to thermal stimuli (5,53). A similar role of PKD in controlling IPAN excitability is of particular interest, since this kinase is capable of sustained activation and of amplifying receptor-mediated signals (26). PKD could thus play an integral role in mediating the increased IPAN excitability associated with the sEPSP or sustained slow postsynaptic excitation elicited in response to low-frequency stimulation of interganglionic connectives (6,32).…”

Protein kinase D: a new player among the signaling proteins that regulate functions in the nervous system

“…In resting cells, PKD is mostly located in the cytosol, with a smaller fraction in the Golgi apparatus. In some specialized cells, PKD also exists in the mitochondria [28] and secretory granules [29] . After activation through the PLC pathway, PKD1 is transported from the cytosol to the plasma membrane, then returns to nonetheless, the localization of overexpressed GFP-tagged PKD and endogenous PKD is identical [30,31] .…”

“…The different lipid-binding specificity of the zinc-fingers C1A and C1B results in their different roles in targeting PKD1 to different destinations [29,33,[41][42][43] . Plasma membrane translocation of PKD1 is dependent on the C1B domain, while its Golgi localization requires the C1A domain and the phosphorylation of loop serines.…”

“…As no interactions have been found between the PH domain of PKD1 and phosphorylated inositol lipids, which are important ligands responsible for membrane localization, this domain is not required for plasma membrane translocation [31,32] or Golgi localization [33][34][35][36][37][38][39] like other PH-domain-containing AGC kinases, such as PKB and the GRKs. However, the PH domain is required for the nuclear export of PKD1 [22,40] .The different lipid-binding specificity of the zinc-fingers C1A and C1B results in their different roles in targeting PKD1 to different destinations [29,33,[41][42][43] . Plasma membrane translocation of PKD1 is dependent on the C1B domain, while its Golgi localization requires the C1A domain and the phosphorylation of loop serines.…”